Prevent opening context menu with all items hidden.

ui/webui/resources/js/cr/ui/menu.js

Index: ui/webui/resources/js/cr/ui/menu.js
diff --git a/ui/webui/resources/js/cr/ui/menu.js b/ui/webui/resources/js/cr/ui/menu.js
index 82013972ff9578a923f38903b159d1c1ef527053..512d1069b9b03475cfe377577b4c03c157a0d107 100644
--- a/ui/webui/resources/js/cr/ui/menu.js
+++ b/ui/webui/resources/js/cr/ui/menu.js
@@ -191,7 +191,7 @@ cr.define('cr.ui', function() {
     hasVisibleItems: function() {

[yoshiki, 2017/05/01 06:36:53]

nit: I think renaming this to "hasVisibleMenuItem" is better for readability.
But it;s up to you.

[yamaguchi, 2017/05/01 06:51:46]

I guess it's been just "item" because the name of this class already contains
"menu". I'll keep the name as it is now.

       var menuItems = this.menuItems;  // Cache.
       for (var i = 0, menuItem; menuItem = menuItems[i]; i++) {
-        if (!menuItem.hidden)
+        if (!menuItem.isSeparator() && !menuItem.hidden)
           return true;
       }
       return false;